Pneumatic signaling



June 9, 1953 E. J. IPOITRAS PNEUMATIC SIGNALING 4 Sheets-Sheet l Filed Jan. 12, 1950 ukbubhk x 8 INVENTOR. Edith: fli'J. Poms, ff M- V June 9, 1953 E. J. POITRAS 4 PNEUMATIC SIGNALING Filed Jan; 12, 1950 4 Sheets-Sheet 2 d 48 a 46 4 A5 INVENT OR.

Edward J 1 02321: s,

Jun 9, 1953 E. J. POITRAS 2,641,689

PNEUMATIC SIGNALING Filed Jan. 12, 1950 4 Sheets-Sheet 3 INVENT OR.

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H I H v Wa'alnd 1 #122 3.

June'9, 1953 E. J. POITRAS 2,541,689

PNEUMATIC SIGNALING Filed Jan. 12, 1956 4 Sheets-Sheet 4 I v A 01 J 9R //30 Y I /.9 \\v\\\\\\\\\\ 495 l 6 (EH u Patented June 9, 1953 UNITED STATES PATENT OFFICE PNEUMATIC SIGNALING Edward J. Poitras, Holliston, Mass.

Application January 12, 1950, Serial No. 138,129

16 Claims. 1

My present invention relates to temperature responsive alarm and signal systems and apparatus of a telegraphic character, in the general sense af transmitting intelligence more or less distantly. More particularly the invention concerns methods and means for adapting pneumatic systems, such as those generally included in standard railway train equipment, to the production of distinctive or specifically informative signals in accordance with the operative status of a thermally responsive detector as determined by an abnormal or excessive heated condition to be detected and indicated. Hence among other uses the invention is especially applicable to detecting and informing of the overheating of railway car journal bearings, the condition generally referred to as a hot-box.

This application is a continuation-in-part of my copending application Serial No. 583,310, filed March 17, 1945.

The hot-box problem in train operation, being old and Well known, requires no detailed explanation here. It is appropriate to note that this problem and the attendant dangers remain acute, particularly so under modern high-speed service and in view of the use demands upon rolling stock under existing conditions.

Various remedies have been proposed for avoiding the dangers of hot-boxes. Some of these have involved valving a pneumatic line of the train. But so far as I am aware provision has not heretofore been made for pneumatically signalling the specific intelligence that a journal box is overheated, as contrasted to some other valving or like pneumatic operation such as ocadapting the train brake air line to the stated signalling purposes. To that end the invention importantly includes the provision of pneumatic and electromagnetic-pneumatic telegraphic relays for impressing distinctively informative signals upon the system. The foregoing and. other improvements in accordance with the invention will be apparent from the following description and in connection with the drawings, in which:

Fig. l is a schematic representation of an example of a system and means of the invention,

suitable for practicing the method thereof, in this instance in association with railway air.

signal equipment which may be conventional; Fig. 2 is a sectional view of one embodiment of a telegraphic relay such as included in Fig. 1 or Fig. '7, on a larger scale;

Fig. 3 is a graph of the pressure and time relationship within a chamber of the telegraphic relay, such as that of Fig. 2;'

Fig. 4 is a partly diagrammatic sectional View other railway air brake equipment serves the dual role of the signalling'as Well as braking; and

Fig. 8 is in part a schematic representation of an example of a further system and means of the invention, in this instance employing an electrical detector and means of impressing an unique code signal upon railway air signal equipment, Fig. 8 also being in part a sectional view showing a typical location of one electricaldetector controlling the coding means.

Referring to Fig. 1, a pneumatic signalling conduit, which may be conventional, such for example as on railroad passenger cars, is indicated generally at I. This conduit 1 is connected as by couplings 2 to one Or more similar conduits extending through adjoining cars, as indicated by broken lines at I, and finally .ter minates at the engine in a conduit line 4. Air is supplied to a conventional or other accumulator 5 as by a pump 3 and is fed into the engine conduit 4, and thence to the train line I, 1, via a regulator valve 6, a check valve 1, and a restriction 8, these latter serially arranged in the engine conduit 4. The pressures are maintained within the conduit system at some normal pressure, say, forty-five p. s. i., by the regulator 6. The state of flow in the line as a whole given by the pressure drop across the restriction 8 in the conduit 4 is measured at an engine signal valve 9 connected in parallel across this restriction. An audible warning of fiow exceeding a critical amount is given by a flow or air from the accumulator and past the engine signal valve 9 to a Whistle I0, this valve 9 being preset for opening actuation upon a particular pressure drop across the restriction 8. The valve 9, diagrammed as a spring-loaded diaphragm type, may be of any suitable form for the differential operation referred to. At convenient points, generally at least one on each car, the train line I, I is provided with means whereby the crew may apply a signal upon the line. One such device is represented at the upper left in Fig. 1, comprising a conductors manual valve I I connected into the train air line I through a cutoff I2 for rendering it inoperative when desired. Valving of air from conduit I by hand operation of such valve II produces a flow through the conduits, including a flow at the restric tion 8.

Connected to the main conduit I in parallel relationship to the usual valving attachments such as the described cond'uctors valve II is a conduit I l communicating between the conduit I and a telegraphic relay device I5, to be further described in connection with Figs. 2, 4 and 5 showing alternative constructions thereof applicable in the system of the invention.

From the relay I5 there extends a conduit I'I having a number of branches and flexible conduit portions I3 disposed. in parallel and each running to a thermally responsive venting means or unit I9. These latter are replaceable plug-like elements or tampions, described in more detail with reference to Fig. 6., one at each heat-subject location to be reported on, in mutual parallel relation so that each is similarly associated with the relay I5.

Inthe instance of railway train installations, eachcar may be equipped with the required number of tampions it, generally at least one at each journal bearing of a wheel axle, renewably inserted for example in the standard brasses of such bearings; see Fig. 6. A given relay I5 may serve a number of cars or each car may be equipped with a relay, it being understood that an assembly of elements such as I4 to I9 of Fig. 1 may be provided wherever appropriate along the air line I, I for the given train. Normal1y, that is, with the warning system in a state of readiness, the conduits I'E, I8, the relays I5 and the line-connected conduits I4 contain compressed air at a pressure equal to that in the train air line I, I", e. g. 45 p. s.,i. Readily available means may be provided, for instance at each car, for testing the operative condition of the system. For this purpose I have represented in Fig. l a hand valve I3 inserted in the conduit IT, in parallel with the several tampions I9, and. so as to be accessible inside or outside the car, or both. Manual opening of such test valve I3 releases the air under pressure in the conduits I7 and I8 and actuates the associated relay I5 in a manner characteristic of the venting of the conduits under a temperature-responsive action at any of the tampions I9. of the hot-box signal system may be investigated at any time.

The system of the invention represented by Way Of example in Fig. l, as applied to a train, functions automatically upon occurrence of a hot-box. The thermally responsive tampion I9 of the particular overheated brass vents air from the conduits II, I8, reducing the assumed normal pressure of 45 p. s. i. therein substantially to atmospheric. This reduction or signal originating in the conduit I8 of the particular thermallyafiected tampion I9 causes the telegraphic relay I5 to begin a series of automatic operations producing an intermittent valving of air' from the main line I via the associated lead-0E conduit I4 and the relay I5 itself.

The relay means may be variously constructed and several alternative forms are described in connection with Figs. 2, 4 and 5. In each instance the construction and arrangement is such that. a regular operating sequence is effective to impress upon the air line I a pre-established code signal. Consequently the associated alarm element, in this instance the whistle Iii in the locomotive, gives the specific informationand only thatthat a hot-box is present. That is, in the system of the invention, the whistle It at the engine emits; blasts in accordance with a predetermined code and the engineer is specifically informed of a hot-box occurrence, as distinguished from any other cause of flow in the train airline I.

Considering now more particularly the signalcoding means, and firstthat of Fig. 2, the signalling or relay-valve unit designated generally at I5 comprises a body I5a apertured at spaced locations for threaded or other attachment of the conduits I4 and 1'! respectively. It contains a plurality of separated chambers. including an upper chamber 20 to which the conduit I1 is connected, a lower chamber 22 having the conduit I l attached thereto, and an intermediate chamber 21, the latter partitioned from the lower chamber 22. as at Ma. Herein such terms as "upper? lower, etc. are merely for convenience in description and without significance as. to the installed position of the relay. The intermediate chamber 2'I is separated from the upper chamber 20 by a snap-acting diaphragmld, to be further described, and. has communication with the lower chamber 22 through a relatively smalldiameter passage or restriction 25, shown in the partition 2Ia. The upper chamber 20, receiving the conduit II, also communicates with the conduit I4 via a passage 26 along a wall of the body I5a and containing a. flow-controlling restriction 21. The conduit I4 opens into the lower chamber 22 through a relatively large restriction 28. The chamber 22 provides a passage in the body I5a, between the conduit I4 and atmosphere, through a communicating port 29 having a closure means or valve 30. v

' The diaphragm 24 which constitutes a common wall between chambers 28 and 2I carries a valve stem 3I having the valve 30 fixed at its lower end, the stem extending through the parti-tion Zia and being guided as by a boss 32 on Thus the, readiness the latter. The valve 30 and its stem 3I are loaded in the port closing direction by a spring 33 herein disposed in the upper chamber 2t and bearing between the diaphragm 2d and an op- "I'he diaphragm 24 has been referred to as snap-acting by which I mean that an operative area of the diaphragm may be caused to snap, jump or click in a positive manner from one to the other of two transversely adjacent positions,

as indicated in somewhat exaggerated fashion by the full and the dotted-line positions in Fig. 2. This action, which may be termed oil-canning, being analogous to that of an oil-can base, I have found takes place definitely, for the given diaphragm, at a characteristic critical difierential in pressure at its opposite faces, and it is importantly availed of in the practice of my invention. For a diaphragm of desired area, the metal or other sheet mate-rial accordingly is selected as to gauge and stiffness to afi'ord the characteristic oil-canning o-r snap-action at a predetermined pressure differential somewhere between the maximum and minimum pressure values attendant on operation of the particular relay, such as the minimum of approximately to a hot-box, or that an operating test is made I by manually operating valve I3. The air in conduit being thus released to atmosphere, the pressure in chamber 2|! is correspondingly reduced from the norm of 45 p. s. i. Consequently the valve is forced open by the relatively greater pressure remaining in the chamber 2| and acting on the diaphragm 24. The lower chamber 22 is thus opened to atmosphere and the conduit l4 and hence the train line I is vented through chamber 22 and the relatively large restriction 23. It will be understood that the strength of spring 33 is selected to permit snap-action or oilcanning of the diaphragm at the predetermined pressure difi'erential, for opening of the valve 3|! under the stated circumstances and for closure thereof under the normal equal pressure conditions in chambers 2|] and 2|. In this connection the effective area'of the valve 30 may be relatively small in comparison with that of the diaphragm 24. The restriction 28 between the lower chamber 22 and the conduit I4 has a diameter sufficiently large to insure that a signal is impressed on the main line upon opening of the valve 30 as described. For example; it preferably has an orifice area at least substantially equal to that of the valve face of the usual conductors manual valve represented at I in Fig. 1.

With the valve 30 open, as shown dotted in Fig. 2, the pressure in the intermediate chamber 2| falls exponentially towards atmospheric, the air being released to the now open chamber 22 via the restriction 25. The pressure differential at the diaphragm 24 in the valve-opening direction thus is reduced. When it reaches the predetermined value between the assumed maximum of p. s. i. and the minimum or zero value at substantially atmospheric pressure, the spring 33 effects snap-action of the diaphragm 24 and forces valve 30 onto its seat, reclosing the port 29. Air from the conduit l4 now again raises the pressure in the lower chamber 22, toward the 45 p. s. i. supply pressure. Attendantly the pressure in the intermediate chamber 2| rises exponentially toward that in the chamber 22. In the course of this increase, upon arrival of the critical pressure differential, the diaphragm 24 again reacts to open the valve 30 whereupon the cycle of operation is repeated. This distinctive operation or signalling continues so long as either a tampion I!) or a test valve l3 remains open. Because the diaphragm 24 is made to respond at a selected critical pressure diiferential the relay is afforded a regular and sequentially repeating operating cycle uniquely determined by the volume of the intermediate chamber 2|, the size of the restriction 25 and the spring 33.

The chart of Fig. 3 depicts the conditions in chamber 2| accompanying the production of a signal series consequent on the described operations, the pressure variation being represented as afunction of time. For concreteness, let it be assumed that the force applied by the spring 33 to the diaphragm24 has a value such that the equivalent pressure thereon is PF; also that the selected critical presure differential for snapwarping or oil-canning action of the diaphragm similarly expressed has a value Pw; and that P5 is the supply pressure as at the beginning of a cycle, assumed in the previous example as 45 At a time to on the graph of Fig. 3 a tampion |9 blows in response to a hot-box (or test valve I3 is opened). The relay |5 accordingly is actuated. The pressure chamber 2| drops expon entially to a value P1 at time n. This pressure is determined and represented by the expression PFPW=P1. At the pressure-time value P1 231 the valve 30 closes and the pressure in chamber 2| builds up exponentially to a determined characteristic value P2 at time t2, which latter conditions are represented by the expression At the pressure-time conditions P2, is the valve 30 again opens and the cycle repeats. It will be noted with reference to Fig. 3 that the valve opening occurs at times designated to, t2, t4, .152 and that closing is at the times t1, t3, t5, t2n+1. By the choice of the values of PF and Pw, for a given Ps, the time ratio of flow and non-flow in the air line and consequentl the ratio of the on and the off time for the whistle I0 is determined. 5

Thus the telegraphic relay I5 acts to vent the train line intermittently, in a patterned manner,

and with a definitely determined frequency. By pre-establishing the value for this frequency, for example by varying the size of the restriction 25 and by appropriate selection of the values PF and Pw for the-spring and the diaphragm re-" spectively, the pneumatic signal is coded to indi-,

cate solely the detected abnormal or'undesired operating condition of a mechanism, such as an overheated hearing or hot-box condition in the case of a train.

Fig. 4 illustrates a modified form of telegraphic relay similarl applicable in thesystem of Fig. l, or that of Fig. '7 later described. The same refer ence numerals as in Fig. 2 are applied to corresponding parts of the Fig. 4 relay, in which the ber 22 communicating with the conduit l4 through a sizeable restriction 28, as inFig. 2.

The valve stem 3| is supported and laterally constrained adjacent its opposite ends by equalarea corrugated diaphragms 36 and 38 respectively separating the chambers 20 and 22a and the chambers 2| and 22. The chamber 22, as in Fig. 2, is ported to atmosphere at 29, and the adjacent end of the valve stem 3| has a valve head 30 for closing and opening this port. At

the other end; the valve stem 3.! carries a. compensating piston 30a. slidable in a bore 30b in the relay body lb. Similarly as in Fig. 2 the supply pressure such as 45 p. s. i. is normally maintained in all of the chambers. 20, 2 l,. 22. and 22a. The interconnections include a passagev 26 on. the relay body extending between the cham ber 22a and the opposite chamber 22, and communicating also with the chamber 20 through a bleeder restriction 21. Chamber 2! and the adjacent chamber 22 are interconnected around the diaphragm 38 b a restriction 25 similar to that in the partition Zia of Fig. 2. A spring 33 bears between the main diaphragm 24 and the. valve body l5bin a generally similar manner as in Fig. 2.

Referring still to Fig. 4, assume now that pressure in conduit I1 is reduced to atmospheric or substantially so by a failure or abnormality in the operating condition of a tended part, as by temperature-responsive opening of a tampion I 9 at a journal hearing (or by test opening of a valve 13). Pressure in the chamber 20' correspondingly falls, and the then greater pressure in the chamber volume 2! upon the diaphragm 24- snaps or click-warps the latter to open the port 29 by unseating the valve 30. The chamber 22 volume is thereby freed to atmospheric pressure and the conduit M is vented through the restriction 28 so as to impress a signal on the pneumatic system, here the signal system of a train.

The opposite chamber volume 22a is reduced to the same pressure as that of chambers; 20 and 22' by means of the interconnections 26' and. 2?. The diaphragms 36 and 38 associated with these chambers 22a and 22 each have the same area, as stated. Likewise the face of piston 39a is of equal area to that of the valve head. 30. Consequently the forces upon the valve stem. 3|

other than those due to the spring 33- and to pressures upon the diaphragm 24 are fully compensated.

On lowering of the pressure in chamber 22 in the open status of the valve 30 the pressure in chamber 2i drops exponentially via the leak constriction 25 between these chambers. As the pressure in chamber 2| falls a critical differential value is reached (see condition "P1, lb of Fig. 3) at which the spring 33 overbalances the chamber 2| pressure and the stifiness of the snapacting diaphragm 24, so that the latter recloses the valve 3%. The pressure thereupon builds up in chambers 22 (and 22a) and, via the restriction 25, in the chamber 2!, exponentially as to the latter. effective area of the snap-action diaphragm 24 exceeds the spring force and the diaphragm stiffness, then, at this critical and preselective value: (see condition Pztz of Fig. 3) the diaphragm 24 snaps reversely and again opens the valve 30. This cycle of operation automaticall repeats again and again until the pressure within the chamber 20 communicating with conduit i! can build up to the supply or line pressure (e. g. 45 p. s. i.). This latter will occur upon reclosure of the point of air venting from the conduit [1, as by replacement of the blown tampion l9 which instituted the signalling cycles (or by reclosing the test valve I3 where opening thereof was the initiating cause).

Referring now to Fig. 5, I have there shown another form of telegraphic relay I5, again embodying means for intermittently venting, a pneumatic signal system so as to impress on it a When again the pressure value at the- 8 predetcrmmedlr coded si nal indicative. of an. are normal condition such as the excessive heating of a journal hearing; or other part, and in particular the occurrence of a hot-box in train operation. In this instance the relay mechanism com.-

prises a starting mechanism. or valve including a body or housing [50 divided into chambers M and 42 by a flexible corrugated diaphragm 4-3. A spring 44 in chamber M bears between the diaphragm 43 and the valve. body I50, the diaphragm having rigidly secured to it a connecting rod or valve stem 45- carrying a valve 46' adapted to close or open an outlet port 46a from the chamber 42.

A venting conduit l7 corresponding to that of the previous views is connected into the chamber 4|. Both chambers ll andv M are shown as subject to the pressure within the supply-line leadoff conduit M, the latter being connected to chamber 4i via a relatively small restriction lla,v

and to chamber 42 through a less restricted passage 42a having an effective area comparable to that. of the valve-controlled port 46a. Since the restriction Ma between chamber ll and the conduit H! has a substantially less area, the major flow is confined to that into or through the chamber 42. Thus when the pressure in chamber M is reduced through the conduit IT, as by venting thereof to atmosphere at a tampion i9 or a. test valve I3, the pressure differential resultant. from the then greater pressure in chamber 42 will deflect the diaphragm 43 compress the spring 134 and unseat the valve head 46. Thus spring 44 exerts a force on the diaphragm Q3 equivalent to a pressure differential which is a small fraction of the supply pressure in conduit I l. 7

Connected to the outlet 46 0f chamber 42 are branching conduits 47 and 48. Conduit. 5'5. contains a relatively narrow restriction 48 markedly limiting any new therein and beyond this restriction it is connected into an air motor 5b] which discharges to atmosphere. Under air flow from the supply in conduit M via the chamber c2 and the branchconduit 41 past the limiting restric. tion 49 the motor 50 acts to drive a movable cam 51, diagrammaticall illustrated as a rotary elementoperatively connected to the motor 5!? by a mechanical movement 52.

The other conduit branch 68 from the outlet 45 of chamber 4'2, having a flow-controlling re striction 48a of relatively larger area than the restriction 39 of the motor conduit 41, terminates in a port 53 opposite and so associated with the cam 5! as to be vented or closed thereby in accordance with the pattern or configuration of the controlling face or peripheral portion of the cam. The air motor and the venting control cam may be assembled with the body or housing- [50 or arranged as a connected unit.

Referring still to Fig. 5., upon ventingv of the conduit H as at a tampion 19 or a test valve {3, the pressure in chamber volume ll drops substantially to atmospheric. The resulting pressure difierential asbetween volumes 4! and 42 causes the valve head 46 to be unseated and accordingly to vent the conduit it through the passages 42a, 42 and 36a. to the branching conduits 4.7 and 48. It should be noted that since spring M. exerts on diaphragm 43 a force equivalent to a small fraction of the supply pressure, the valve head 46 remains unseated during the whole time conduit 11 is vented. The cam-associated conduit 48 receives the major outflow by reason of the more limiting size of the restriction. 49 in the. motor conduit. 41. However, the pressure difierence as between that in conduit 41 and the atmospheric outlet of the motor causes the latter to drive the cam i, alternately presenting closing and opening portions thereof in cooperative relation to the outlet 53 of the conduit 38, thereby venting the latter intermittently in predeterminedly controlled fashion. Hence a signal or signal series is impressed on the train air line or other pneumatic signal system via the conduit it, as regulated by the particular sequence of the venting and closing formations of the cam. These may be proportioned and arranged, or different cams interchangeably installed, to afford any desired ratio of on and off time for the pneumatic indicator or whistle H for example to effect any desired sequence of long and short blasts preselected as informative of the particular deleterious or overheated condition, such as a hot-box. From the foregoing it will be understood that the air flow at the restriction 49 and any possible leakage at the cam nozzle 53 when the, latter is closed is insuflicient to cause operation of the engine sig nal valve 9; also that the valve head d6, once opened in response to venting of the conduit H, remains open for the duration of such venting.

Turning now to Fig. 6, I have there illustrated one of the thermall responsive venting elements or tampions, indicated as a whole at !9. In Fig. 6

a portion of a standard or other brass, such as 1 bears upon an axle of a railway car, is indicated at 359. A thrust lug 59a of the brass is crossdrilled as at fill and 6! and tapped to receive at one of these apertured portions the coupling nut Hint of a flexible conduit section it, and to receive the tampion unit l9 in the other apertured portion. It will be understood that the brass 59 of which a portion is shown in horizontal section in Fig. 6 is in heat-subject relation to the particular part of which the temperature condition is to be indicated, in this instance a railway wheel journal, as more fully indicated in Fig. 8.

The improved tampion as here illustrated comprises a generally cylindrical and externally threaded body I9a of a material of high thermal conductivity. The tampion body is axially bored and is countersunk at either end, as at 62, 62a, such formation at the outer end 52 being of a non-round or internal hex form to fit a wrench for installing or removing the tampion with respect to the brass 59.

The bore of the tampion body, between the countersunk portions, includes a reduced cylindrical vent 63 and a communicating radially enlarged portion as at 54 providing a seat, shown at the end of the vent 63 which is nearer the outer end of the tampion. The vent 63 and the associated seat 64 are filled with an eutectic alloy 65 selected to have a characteristic temperature of melting or liquifying as appropriate to the particular use, as for example 350 F. for the car journal bearing installations.

Thus in the embodiment of Fig. 6 should the brass 59 become heated to a temperature of 350 F., under improper lubrication or other fault, the body of the valve or tampion I9 .quickly conducts such heat to the contained eutec'ticalloy and causes it to liquify, the boundary region of the alloy contiguous to the containing body melting before the internal region. If a difference of pressure exists between the two ends or countersunk portions 62, 62a of the tampion, the melted alloy will. be expelled. However, the alloy at the relatively narrower-vent portion 63 completely liquifies ahead of that in the rela tively voluminous seat 64. Hence the alloy en- 10 largement or collar in the seat 64 temporarily reinforces the alloy structure in the vent (it against the force attendant on the differential pressure, and then upon the delayed liquification of the collar portion the entire alloy plug or structure inthe bore portions 63 and 54 will suddenly let go and blow clean.

. From the foregoing description of the improved heat-responsive tampion or valve means of Fig. 6 and in connection with the description of Figs, 1 to 5, it is evident that the supply-line pressure, assumed for example as 451p. s. i., creates a pressure diiferentialof corresponding value across the alloyinsert 65 when the particular conduit [8 is sealed off by a tampion lS. The signal system is then in a state of-readiness. On arrival of the specified temperature the alloy insert melts and blows, dumping the conduits l1 and .I8 and thereby actuating a corresponding telegraphic relay IS in the manner already described.

In connection with Fig- 1 the invention has been disclosed with reference to a pneumatic signalling system, particularly a train air signal system. Some railway cars, particularly freight cars, are not equipped with air signal lines. In such case, or alternatively even where an air signal line is present, the principles and means of the invention may be incorporated with the conventional train air brake systemyadapting the latter to serve the dual role of distinctive or pre-coded signalling as well as that of braking.

Accordingly, referring now to Fig. '7, I have there shown a conventional or other air brake may be the conventional components of a trainv air brake system. In combination with them and with the air brake, line H, II and the engine conduit 14 I haveshown in; Fig. 7 further devices whereby the pneumatic braking system is adapted to serve additionally for signalling, and particularly as an overheated journal bearing or hot-box alarm system.

' To that end there is further provided at the locomotive, in the conduit M, a flow restriction IIB, and shunted across the latter in a conduit 8|, 8] a signalling valve 19 adapted to measure the pressure drop across the restriction i8 should a flow of air occur. Operatively connected to the valve 79 is a Whistle 80 for giving an audible warning should this pressure drop exceed a critical value. The restriction T8, the signalling or pressure-drop measuring valve 79 and the whistle 80 have the similar function as the corresponding elements a, 9 and In of Fig. 1.

Branching from the air brake line H, H at appropriate locations (such as one for each car and preferably at each truck) is a signal conduit I4 and associated relay, conduit and tampion elements 15, ll, I8, 19, with if desired a manual test valve l3. Each such assembly of elements is disposed in parallel relation to the" brake elements 82. Similar reference characters as in Fig. l are applied to' corresponding elements this respect in the systems of both these figures.

11 InFig. 7 there is additionally included in the assembly of signalling parts .a regulatoryalve 9.9 ofconventional or preferred construction, inserted in the conduits I4 ahead of eachrelay I5, that is, between them .and the air brake line II. As stated, the pneumatic conduit II, 'II' ,of Fig. 7 represents a train air brake line communicating at the locomotive with the conduit "It and the described elements I3 to SI. Also at that location the brake valve 83 is inserted in the conduit .14; forventing the line, in the customary manner to set the brakes.82 either manually or automatically. It is desirable that the release of air pressure to the brakes by operation of the valve83 does not at the same time sound the whistle .83 For this purpose there is inserted. in the .conduit SI of the signal valve 19 a cut-out cook 84 mechanically or otherwise connected to an operating member of the brakecontrolling valve 83, as indicated at 85. Any

preferred form of cut-out means 84-435 may be employed, that shown being similar to known cut-out arrangements, such as illustrated .for example in Fig. 6 of U. S. Patent No. 823,114 of June 12, 1906, to Gerard.

The regulator SB previously mentioned, shown in Fig. 7 installed ahead of the relay or signalling valve I desirably is provided in order that venting of the tampion conduits I1, is will not cause the brakes to be applied. Such regulator 98 serves to limit the pressure drop in the brake conduit II to a value suflicient for the distinctive signalling purposes of the invention but not such as to cause any setting of thebrakes 82; Assume for example that the regulator valve 16 at the locomotive normally maintains a pressure of approximately 60 p. s. i. in the system; also that the brakes 82 will start to be set only when the pressure'in the air brake line H, II, it falls to say 4G p. s. i. In such cases the relay-associated regulators to will be adjusted to prevent a pressure drop in the line below say 50 p. s. ip. Correspondingly the engine signal valve 1'9 is set for actuation by a pressure drop across the constriction I8 of something less than p. s. i. Thus the code signalling attendant on heat release of a tampion I9 and the action of the associated relay I5 is free to produce the predetermined signal at the whistle '80 similarly as explained in reference to Figs. 1 to 6, wholly without interference with the braking function "leased in response to an overheated condition there, the corresponding conduits I8 and I! are vented and the relay 5% acts to vent the conduit I l in the determined intermittent fashion as described in connection with Figs. 2 to 5. The air brake lin TI is thereby vented through the relay !5 to impose on the line a distinctive signal in accordance with the pie-established code. Theattendant pressuredrop in the conduit H is restricted by the regulator valve 98 to. a value substantially in excess of the assumed 40 p. s. i. braking pressure limit, such excess value being 50 p. s. i. in the given example.

This pressure reduction of 10 p, s. i. from the normal 60 p. s. i.'value maintained in the line 12 II by the regulator 56 institutes a flow at the restriction '58, measured by the signal valve 79 which accordingly actuates the audible signal or whistle 80, similarly as in the system of Fig. 1. Thus the whistle will emit blastsat all times when the pressure in the air brake conduit TI is reduced in accordance with the operation of a relay'i5. Since the latter in turn is activated by a thermally responsive tampion I9 at a bearing brass, the distinctive coded signal thus impressed on the conduit II through the medium of a relay #5 conveys the specific intelligenceand only that particular informationthat an overheated bearing or hot-box condition exists. This distinctive signalling will continue until the initiating tampion I9 is replaced.

In some instances, as for example on freight trains not equipped with air signal lines, it may be desirable to include provision for signalling through the medium of the air brake line for,

purposes other than automatically informing of a particular abnormal condition such as a hot box. In accordance with the invention as disclosed for example in connection with Fig. 7 the described provisions for utilizing a determined upper fraction of the air brake pressure make such other signalling readily available. For this purpose, referring to Fig. 7, a supplemental valve III, including if desired a cut-01f II2, which may be similar to the conductors manual valveII and cut-oil 52 of Fig. '1, may be connected into each or any of the signal conduits I4 behind the corresponding regulator 99, that is, between the latter and the automatic signalling means or relay i5, as indicated at the upper left in Fig. 7. Manual or other operation of such valve HI, which is in parallel to the particular relay and hot-box alarm means, will effeet a corresponding signal at the locomotive by sounding the whistle 8B in the example illustrated. Such signalling venting as at a valve III may be in accordance with a prearranged telegrapic or other code or otherwise.

Fig. 8 depicts a still further embodiment of the invention and of means for practicing the same. As with Fig. l a pneumatic signalling conduit is indicated generally at I. This conduit I is connected as by couplings 2 to one or more similar conduits extending through adjoining. cars, as indicated by broken lines at I, and finally terminates at the locomotive in a conduit line I04. Air is supplied to a conventional accumulator 5 as by a pump 3 and is fed via a reducing valve Iiii where the pressure is reduced to a standard value and via a combined strainer, check valve and choke I67 to the engine conduit IE4 and thenceto the train line I, I. A branch of the conduit IE4 is connected to the locomotive signal valve 98, and another branch to the train signal pipe I. The locomotive signal valve is provided with a whistle ace and a. pressure gauge 99.

As in the previous embodiments already described the air line I may be equipped with a conductors signal valve II, I2, generally one or more for each car. Connected to the main conduit I in parallel relationship to the usual valving 'relay I is a series of electrical thermostatic switch or detector elements desirably selected for rugged and jar-resistant construction and repeat capacity as well as good thermal performance, these preferably being such as disclosed in U. S. Patents Nos. 2,090,407 and 2,257,990, to W. J. Turenne and dated August 17, 1937, and October '7, 1941, respectively. Since these detector elements here serve the similar function in this electrically detecting embodiment of my invention as do elements IS in the all pneumatic embodiments of Figs. 1 through 7, these thermally responsive units are designated by the same numeral I9 as in the previous views with the addition of an exponent E.

These thermal detector switches ISE are placed in intimate relationship with the bearing structure of the particular journal box (or other part to be protected) and are interconnected electrically in series relationship. Preferably the thermal detector switches I9E are of the normally closed type, that is, which open a circuit upon arrival of the abnormal heat condition, the switches returning to the usual closed status when cool.

In the system of Fig. 8 the thermal detector units I9E in the normal condition of readiness establish a continuous circuit between one another, a battery H6 or other electric source and an electro-magnetic relay III. A manual test switch H3 may also be included in the series circuit. Thus with the series detector circuit in ready condition the detector units IBE are closed and the electro-magnetic relay H1 is opened, as in Fig. 8,

When the relay H1 is de-energized associated contacts H8 close and establish two parallel circuits through the battery or power source Ht. One such circuit is through the electric motor H9 which operates the signal coding means. The other circuit is from the battery to the outer end of the motor shaft I20, insulated from the motor by insulating material I20a, to a rotary cam switch [H on the motor shaft I20 provided with contact points or segments I22 wiped by a contactor I220. connected to a solenoid I23 of a solenoid valve H5, the other side of the solenoid being connected to the battery H6. This solenoid valve H5 controls the conduit I4 leading from the main line I and thus is pneumatically coupled to that line. The venting orifice of this solenoid valve H5 has an area similar to that of the conductors hand valve II, thereby to vent th train line I in response to call by a detector unit IIlE or under opening of the test switch I I3.

In operation, assuming that a thermally responsive unit IQE is actuated by arrival oi the abnormal condition, a hot-box in the illustrated instance, the circuit containing the elements IQE accordingly is broken, the relay III is de-energized and the contacts H8 close. The described two circuits there established cause actuation of the motor H9 and set up a circuit through the rotary cam switch I2I, its points I22 and the valve-operating solenoid I23. Rotation of the cam I2I by the motor H9 causes periodic making and breaking of the circuit at the contactor I220. with corresponding periodic energiz ing of the solenoid I23 and resultant peIlOdlC venting of the conduit I4 by the electro-magnetic valve H5, in a generally similar manner as taught in connection with Figs. 1 to 7. By selected arrangement of the segments or points I22 circumferentially about the cam I2I any desired predetermined code may be impressed upon ing the trucks, wheel axles and their journal the air signal line. The ratio of the t" e of venting to that of non-venting may be adjusted to avoid objectionable depletion of the train line.

As illustrated at the lower right portion of Fig. 8 the thermally responsive electrical switch units I9E are disposed in position-to respond to overheating of the bearing element I30, I30 of the rail-way car journal I3I, such bearing being conventionally indicated on Fig. 8 as of the roller type generally comprising inner and outer races having the bearing rollers between them. In such case the switch units I9E are installed preferably by embedding them as shown in the bearing housing 59R in which are mounted the roller bearings I30, I30. Where plain bearings are used, commonly known as brasses, the switch units IQE may be embedded therein as previously referred to in connection with Fig. 6. It will be understood that alternative circuits are available in the practice of the invention, the air line signal coding means I5 being arranged in a thermally responsive circuit which is either made or broken on arrival of the abnormal condition thereby to institute the coded signalling.

My invention is not limited either as to method or means to the particular steps or embodiments as illustrated and/or described herein, its scope being pointed out in the appended claims.

I claim:-

1. In combination with a railway car includbearings, the car equipped with'a pneumatic line adapted for signalling, normally closed venting means in heat-subject relation to one or more of the bearings for opening in response to overheating thereof, and telegraphic pneumatic relay means comprising a chambered body having a port and a conduit therefrom to the venting means for actuation of the relay means thereby, said body having-a passage connected in communication with the pneumatic line of the car and leading from the body to atmosphere thereby to vent the line to impress a signal thereon,

closure means controlling and normally blocking signalling venting of the passage, and periodic pressure-responsive means associated with the body for so predeterminedly operating the closure means on opening of the heat-subject venting means as to distinctively code'the signal impressed on the pneumatic line, said relay means 7 being interposed directly between the venting means and the pneumatic line.

2. The combination according to claim 1 in which the periodic pressure-responsive means comprises a snap-action diaphragm forming a chamber wall in the body and responsive to pressure differentials thereon, and a restriction interconnecting the chamber and the passage leading from the body to atmosphere thereby alternately to relieve and to create a pressure differential effective on the diaphragm in accordance with a pre-established time factor.

3. The combination according to claim 1 wherein the periodic pressure-responsive means comprises an air motor, and a movable cam operatively connected with the motor and presenting venting orifices of a selected pattern, the passage leading from the body to atmosphere extending to and cooperating with the cam for venting thereby.

4. In a fluid-pressure signal system associated with a part at which undue heating is to be determined, in combination, a thermo-responsive device in heat-subject relation to the part, a fluid-pressure cycling relay device for imposing predetermined signals on the system, said cycling relay device comprising a valve chamber havin a fluid pressure supply inlet, an outlet to atmos: phere and an outlet valveja snap-action diaphragm operatively connected to the valve; a chamber wherein the diaphragm defines a common wall between opposed volumes; spring means biasing the diaphragm for valve closing under substantially equalized pressure of the opposed volumes; passage means including-,restric. tions foradmitting the pressure fluid to one volume and for admitting it to or releasing it from the other volume accordingly as the valve is closed or open respectively; and port means controlled by the thermo-responsive device to vent the first-mentioned volume thereby to institute and continue during such venting a periodic opening and closing of the valve according to a time factor conjointly predetermined by the spring means, said other volume andthe-admission-relief restriction thereof, the cycling relay device being interposed between the thermoresponsive device and the fluid-pressure signal system so that the imposed signals characterize occurrenc of undue heating.

5. In a fluid-pressure signal system associated with a art at which undue heating is to be determined, in combination, a thermo-responsive device in heat-subject relation to the part, a fluid-pressure cycling relay device for imposing predetermined signals on the system, said cycling relay device comprising a valve chamber having a fluid pressure supply inlet, an outlet to atmosphere and an outlet valve; a snap-action diaphragm operatively connected to the valve; a chamber wherein the diaphragm defines a common wall between opposed fluid-pressure volumes; spring means biasing the diaphragm for valve closing in the absence of an overbalancing pressure differential in the opening direction; restrictions communicating between the supply and both volumes normally to create substantially equal pressures therein, the restriction at one side of the diaphragm reversely operable to relieve the pressure thereat when th valve is open thereby to permit reclosing of the valve under spring-influenced snap-action of the diaphragm; and venting port meansat one side of the diaphragm and controlled by the thermoresponsive device so as to create an overbalancing pressure differential in the valve-opening direction thereby to initiate and continue during operation of aid means alternate opening and closing of the valve in predeterminedly timed sequence, the cycling relay device being interposed between the thermo-responsive device and the fluid-pressure signal system so that the imposed signals characterize occurrence of undue heating.

6. In combination with a railway car including the trucks, wheel axles and their journal bearings, the car equipped with a pneumatic line adapted for signalling, thermo-responsiv means in heat-subject relation to one or more of the bearings for actuation in response to overheating thereof, an automatic telegraphic signal-coding relay device including a pneumatic outlet to atmosphere and a conduit connecting the relay devic into the pneumatic line, the relay device further including a movable closure element for the outlet intermittently to vent and to restrict the same according to a predetermined time pattern imposing distinctively coded signalling impulses on the pneumatic line, a motor governing the intermitting action of the movable closure element, and control means for the motor subject to the thermo-responsive means whereby actuation of the latter on overheating of a hearing starts and continues operation of the motor.

'7. In a fluid-pressure signal system associated with a part at which undue heating is to be determined, the system including a pressure-fluid line having signal transmitting capacity, an auto matic telegraphic signal-coding relay device operatively interposed between such'part and the pressure-fluid line, said device comprising a, hollow body containing first and second pressure volumes and a diaphragm defining a common wall between them, inlet and outlet passage means for the respective pressure volumes, the inlet passage means leading from the pressure-fluid line and the outlet passage means leading to atmosphere,

the outlet passage means of the first pressure volume having thermo-responsive openable closure means operatively subject to the mentioned part and normally closed in the absence of undue heating of such part, the outlet passage means of the second pressure volume having a normally closed valve connected to the diaphragm for operation thereby on thermo-responsive opening of the first-pressure-volume outlet passage means, and periodic flow-modifying means for the passage meansof one of said pressure volumes for so predeterminedly modifying the flow thereat as to intermit in distinctive coded manner the signals relayed onto the fluid-pressure line.

8. The combination according to claim 7 Wherein the periodic flow-modifying means comprises a calculated restriction in the passage means of the second pressure volume, the body of the relay device including a rigid wall carrying said restriction, said wall presenting slide-bearing means for the Valve.

9. The combination according to claim 7 Wherein the periodic flow-modifying means comprises a calculated restriction in the passage means of the second pressure volume, and the valve is connected to the diaphragm by a stem extending through both pressure volumes and having a pressure-compensating piston at the end thereof remote from the valve.

10. The combination according to claim '7 wherein the periodic flow-modifying means comprises an air motor receiving actuating pressure from the outlet passage means of the second pressure volume, and a movable cam connected for operation by the motor and presenting vent orifices of a selected pattern, said outlet passage means of the second pressure volume including a conduit extending to the cam for venting by the orifices thereof.

11. In combination with a railway car and an air brake system therefor including a brakeapplying valve, the car having trucks, wheel axles and journal bearings, a thermo-responsive detecting device in heat-subject relation to a journal bearing of the car and having a venting outlet for the air brake system, coding relay means for characteristically intermittently venting the air brake system via said outlet upon thermal response by the detective device, regulator means limiting the pressure drop in the air brake system under such venting by the relay means to a selected value less than that for actuation of the brakes of the system, said relay means interposed between the thermal responsive device and said regulator means, a signal element operatively connected in the system and adapted for actuation in response to such limited pressure drop, a cut-oil for the signal element, and means operatlvely connecting the cut-off and the brake-applying valve.

12. In a fluid-pressure signal system associated with a part at which undue heating is to be determined, the system including a pressure-fluid line having signal transmitting capacity, a thermoresponsive electrical switch in heat-subject relation to said part, a conduit connected into the pressure-fluid line and providing a venting outlet to atmosphere for imposing signal impulses on the line, and automatic telegraphic signal-coding relay means operatively between the thermoresponsive switch and the venting outlet and comprising a solenoid-operated valve for said outlet, an operating circuit containing said valve, a coding circuit and electrical means therein controlling the valve operating circuit to cause the valve intermittently to vent and to retrict the outlet according to a predetermined time pattern distinctively coding the signal impulses on the line, and an electrical circuit controller in circuit with the thermo-responsive switch whereby actuation of the latter on overheating of the heat-subject part activates the valve operating and the coding circuits.

13. Apparatus for imposing on a fluid pressure system having signalling capacity signals to indicate undue heating of an associated heat-liable part, comprising a thermo-responsive electrical detector switch in heat-subject relation to such part, a valve for venting the system, a solenoid and coding control means therefor for operating the valve so as to impose distinctively coded sig, nals on the system to characteristically indicate heating of such part, and electric initiating means responsive to the detector switch to activate the valve solenoid and the coding control means.

14. Apparatus according to claim 13 wherein the coding control means comprises a periodic make-and-break device for the valve-operating solenoid in a circuit therewith subject to the electric initiating means.

15. Apparatus according toclaim 14 in which the periodic make-and-break device includes an electric operator therefor also in a circuit'subjec to the electric initiating means.

16. In a fluid-pressure signal system associated with a part at which undue heating is to be determined, a thermo-responsive electrical switch in heat-subject relation to the part, a solenoid- Y operated valve connected into the system to vent and to close it thereby to impose signal impulses thereon, a solenoid operating circuit including periodic make-and-break means, an electric device to actuate the make-and-break means, a circuit containingsaid device, and circuit control References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 679,945 Christensen Aug. 6, 1901 700,766 Harris et a1 May 27, 1902 800,751 Marrs Oct. 3, 1905 823,114 Gerard June 12, 1906 928,459 Kieselhorst July 20, 1909 1,001,084 Sauvage Aug, 22, 1911 1,058,993 Marvin Apr. 15, 1913 1,068,675 Lightfoot July 29, 1913 1,270,954 Jordan et al. July 2, 1918 1,318,369 Fischer Oct. 14, 1919 1,512,456 Carmen Oct. 21, 1924 1,600,527 Woodring Sept. 21, 1926 1,758,711 McCune May 13, 1930 1,820,147 McCune Aug. 25, 1931 1,910,513 Yancy May 23, 1933 2,114,762 Edmonds Apr. 19, 1938 2,181,225 Campbell Nov. 28, 1939 2,187,958 Vigne et a1 Jan. '23, 1940 2,304,839 Matheson Dec. 15, 1942 2,339,436 Stephenson Jan. 18, 1944 2,357,620 Thomas Sept, 5, 1944 2,385,487 Baughman Sept. 25, 1945 2,420,924 Whittaker May 20, 1947 2,429,817 Jones Oct. 28, 1947 Austin Nov. 1, 1949 

